The present disclosure relates to a washing machine with a so called direct drive system. More particularly, the present disclosure relates to a washing machine comprising a tub, a drum rotatably mounted inside the tub, a shaft centrally connected to the drum for transmitting the drive force of a motor, a coaxial support connected to the rear portion of the tub and having a seat for a first bearing supporting an end of the shaft opposite the drum, a stator of the motor supported by the coaxial support and having a plurality of magnetic cores, a rotor of the motor provided with permanent magnets and connected to the shaft, and a second bearing for supporting a portion of the shaft between its end and the drum.
This kind of washing machine is disclosed by FR-A-1354594. In this known machine the coaxial support is cup-shaped and is provided, on its concave side, with a cup-shaped auxiliary support to which the annular seat of the second bearing is fixed. The two cup-shaped supports define together a round chamber where the rotor and the stator are mounted. In this known construction, where the tub and the two above supports are made of metal, the annular seat of the second bearing is a metal hub with an external annular flange interposed between the rear portion of the metal tub and a central portion of the cup-shaped auxiliary support.
In view of the above features, the installation of the direct drive motor system to the washing machine is quite complex since at least two pieces have to be fastened to the tub, i.e. the cup-shaped “external” support and the cup-shaped “internal” auxiliary support. This complexity has prevented any appliance producer from adopting this technical solution.
Another similar solution is disclosed by U.S. Pat. No. 5,809,809 where the motor, with its stator and rotor, can be detached as a single component from the shaft, since the rotor present a central hub supported by the disk-shaped housing by means of two roller bearings. Even if this solution presents the advantage of keeping the components of the direct drive motor all together, on the other hand it is quite complex from a mechanical point of view and presents a higher number of components if compared to the traditional direct drive systems. Moreover in this solution all the mechanical loads of the drum are supported by an outside component (the disc-shaped motor) fixed on a rear face of the tub. This concentration of forces in the fastening area of the motor can create problems of reliability and safety.
Further features and advantages of the present invention will be clear from the detailed description of specific embodiments.